Pneumatic hammer.



C. B. FRENCH. PNEUMATIG HAMMER. "APPLICATION FILED 111111.19, 1911.

Patented Apr. 9, 1912.

51111 vanto@ A v 1.1111 WARUI ward movement, as conditioned to admit air behind the ram."l Fig. 3 shows such condition; air under pressure Ienters the cylinder through thef port Z1 andldrives the ram forward to deliver its blow, the large passage Z4 being open tlo allow air infront of the ram to escape figeelypasttlie disk-valve H4. After the blow beenI striclc the attendant moves the D-valveH rearwardly to close the port d1 and connect it through the throat of the valve with the exhaust port d and at the same time uncover the port Z2 to admit air to the forward end of the cylinder; the same movement seats the disk-valve H4 and thus closes the cylinder so that the compressed air entering at the orifice Z3 may exert its force on the ram and return it to position at the rear of th cylinder ready for the next impact.y Byiis arrangement the ram is at all times un" er the control of the attendant,

and the distance of travel and force of the blow may be varied as desired.

In the cap vD2 is a plunger K having a head K1 projecting into the cylinder and subject to the expansive force of a heavy helical spring K2 abutting against the rear face of the head andthe inner face of the cap. A stuiiing-box K3 prevents the escape of air around the plunger, and a nut K4' on. the screw-threaded outer end of the plunger affords means for4 adjusting the amount of projection ofthe head within the cylinder. This .mechanism cushions the return stroke ofthe ram and thus relieves the cap from such strong return impact and also performs another important function in storing a portion of the energy expended in the rearward movement of the ram, again returning it to the ram in initiating the forward or edective stroke. The spring K2 is compressed by the impact of the ram and is held partially compressed by the air pressure acting on the forward face of the'ram until the D-valve is thrown to admit air to the port d1 and to -open the disk-valve H4. Thus released the spring forces the ram forward, overcoming its inertia, and permitting the air pressure to act upon the rear face of the ram while the latter is in motion, aiding materially in increasing the velocity ofthe movement and force of the blow.

L is a motor having a shaft L1 carrying on each of its overhung ends a sheave or narrow drum L2 around which is taken one or more turns of the cable N, secured at its ends. By rotating this shaft in one direction or' the other the car A on which the movmeans? tor is mounted may be moved along the.'

rails A2 as the work progresses.`- The motor may be of any ordinary or approved type and is shown as receiving air from the chest D4 through hose connections L3 L4 from ports, not shown, controlled by. a handlever L5 and valve-stem Ls through a valve, not shown; any suitable arrangement of valve and ports will serve, as will be understood without complete illustration.

The hammer as shown and described is strong and etlicient and is eminently simple in construction and operation.

Modifications may be made in the forms and proportions without departing from the invention, and parts may be used without. the whole. The cylinder may be mounted otherwise than upon a car or truck, and the traversing and directing means may be varied or omitted to suit the requirements of the service to which the invention may be adapted.

1. In a hammer of the character set forth, a cylinder, a ram loosely mounted therein, a spring actuated plunger at one end of the cylinder for coperation -with said ram, a chest adapted to receive liuid pressure and having admission ports leading to the ends of said. cylinder, and an exhaust port, a valve controlling such ports, a valve-stem -,for said valve, an auxiliary exhaust passage leading from one end of said cylinder, and a valve carried onsaid valve-stem for controlling said passage.

2. In a hammer of the character set forth,

a cylinder, a ram loosely mounted therein, a'.

chest on said cylinder adapted to receive fluid pressure and having admission port-s leading to the ends of said cylinder, and an exhaust port, a slide-valve controlling such ports, a valve-stem on said slide-valve extending longitudinally of said cylinder, aV

casing en sald cylinder having an open end, an exhaust passage leading from the interior of said cylinder at one end to said casing,

and a disk-valve on said valve-stern. moving with said slide-valve and controlling the 'open end of said casing..

In testimony that I claim the invention above set forth I atrlx my signature, in presence of `two witnesses.

- CHARLES B. FRENCH.

"Witnesses lMICHAEL W. KELLEY,

FRANCIS J. WALTY. 

